共查询到20条相似文献,搜索用时 31 毫秒
1.
J. Heintze G. Heinzelmann P. Igo-Kemenes R. Mundhenke H. Rieseberg B. Schürlein H.W. Siebert V. Soergel H. Stelzer K.-P. Streit A.H. Walenta 《Nuclear Physics B》1979,149(3):365-380
The decay K+ → e+υγ has been investigated. For the structure-dependent part with positive γ-helicity (SD+) the branching ratio is obtained from 51 ± 3 events observed in the kinematical region Ee ? 235 MeV, Eγ > 48 MeV and θeγ > 140°. For the corresponding part with negative γ-helicity we obtain an upper limit Γ(SD?)/Γ(SD+) < 11 (90% CL) from the sample of electrons with energies 220 MeV ? Ee < 230 MeV and with no γ in the backward direction. This upper limit implies that the ratio of structure-dependent axial vector amplitudes lies outside the region .For the decay the limit 90% confidence level) was found. 相似文献
2.
O. Erriquez S. Natali S. Nuzzo A. Pullia F. Romano D.C. Colley G.T. Jones L. Lowe S. ONeale S.J. Sewell G. Bertrand-Coremans H. Mulkens J. Sacton C. Vander Velde-Wilquet J. Wickens V. Brisson P. Petiau T.W. Jones 《Physics letters. [Part B]》1978,77(2):227-232
For e+ energy > 0.3 GeV and 10 GeV < visible energy < 100 GeV we find that: (i) ; (ii) 1.2 ± 0.5 neutral strange particles are produced per μ?e+ event; (iii) the lifetime of possible positron-parent particles is < 3 × 10?10 s (90% C.L.); (iv) the cross section for direct e+ production via the neutral current is < 0.2 times that via the charged current (90% C.L.); (v) the cross section for producing heavy leptons, L+, decaying into e+ … is < 0.7 × 10?3 times that for μ?production, implying M(L+) > 10 GeV. 相似文献
3.
The emission spectrum of the He2 molecule has been rephotographed in the ~4000–~5700 Å region and the , , and transitions analyzed. The 4dδj3Δu, 4dπj3Πu, and states have been characterized through v = 2 and the 4dδJ1Δu, 4dπJ1Πu, , and states for v = 0. The term levels for these perturbed and l-uncoupled states have been confirmed (a) by analyses of bands with common levels from Δv = 0, ±1 sequences and (b) by analyses of the transitions between the above states from 4d and 4s and the and states associated with 3pσ. Molecular constants are reported which have been partially corrected for the effects of l-uncoupling and the homogeneous perturbations between the state pairs J, H and j, h. 相似文献
4.
《Journal of Physics and Chemistry of Solids》2004,65(8-9):1381-1390
5.
From a study of (p,t) reactions on 31P and 30Si it is suggested that in 29P the states with and , the pair , , and the pair , are related by weak coupling of a s proton with the states 01+, 02+, 21+ and 41+ respectively of 28Si. Completely atypical L = 2 angular distributions have been obtained for the and states in 29P and it is suggested that this is due to contribution by two-step processes. 相似文献
6.
V. Privman 《Physica A》1984,129(1):220-224
We employ the recently proposed scaling theory for first-order transitions to derive a detailed prediction for the large-argument behaviour of the critical-point scaling function of the reduced fourth order cumulant correct up to a term exponentially small in L/ξ(T). 相似文献
7.
Emission spectra for the electronic transitions , , , , , , , and of 4He2 are reported and the electronic structure of the triplet states associated with v = 0 of (1σg)2(1σu) nsσ and ndλ characterized. The energy levels comprising the and the manifolds exhibit strong channel mixing, while the mixing of the with the channel structure is relatively minor. Models based on multichannel quantum defect theory are used to aid in the spectral assignments and to correlate the observed level structures. We show that three-limit and two-limit models adequately represent the bulk of the observed and channel structures, respectively. 相似文献
8.
Cyclotron resonance of electron and holes have been optically detected at 70 GHz and at 1.8 K in n-type CdTe. The bare effective masses, in unit of the free electron mass, are found to be: , , , and , , for H // <111>. The Luttinger valence band parameters deduced from these measurements are: γ1 = 5.3 ± 0.5, γ2 = 1.7 ± 0.3 and γ3 = 2.0 ± 0.3, in fair agreement with the calculations of Lawaetz. 相似文献
9.
Emission spectra for the electronic transitions and of He2 are reported and the electronic structures of and characterized. The energy levels associated with exhibit extensive channel mixing, which leads to a breakdown of conventional band models for the higher n1-members of these Rydberg “series.” However, a model based on multichannel quantum defect theory quantitatively correlates the observed level structures. The higher-energy () portions of the channels can be represented by two eigen-quantum defects μ1 = 0.225 and μ2 = 0.930 and the close- to loose-coupling matrix elements and . The inclusion of energy dependence in the μα's leads to quantitative correlations for all n1-values. 相似文献
10.
A rigorous derivation of the range of validity of the asymptotic relation is presented. 相似文献
11.
M. Andrews 《Physics letters. A》1981,83(3):95-97
A simple physical realization is found for the time-dependent harmonic oscillator equation , for its auxiliary equation , and for the Ermakov invariant. Through generalization of the model, a set of invariants is obtained for a system of equations of the form . 相似文献
12.
The emission spectrum of the He2 molecule has been rephotographed in the ~3200–4100 Å region and the , , and transitions analyzed. The g, k′, and n states, which have not been reported previously, are characterized through v = 1, 2, and 1, respectively. Several small accidental perturbations have been observed in the rotational manifolds of the k′ and n states. 相似文献
13.
Harry Partridge Charles W. Bauschlicher James R. Stallcop 《Journal of Quantitative Spectroscopy & Radiative Transfer》1985,33(6):653-655
Potential energy curves for the , and states of N+2 that dissociate to N () and , have been determined from a complete active space self-consistent field calculation. The state is found to be significantly bound (De = 2.68 eV) with a minimum at 1.72 Å. 相似文献
14.
Spectral luminescence characteristics of the Cs2Na(Er, Yb, Y)Cl6 type upconverter have been measured in the range 300–650 K. A nearly sixfold decrease of the emission intensity of an upconverter was observed in the green area. This emission corresponds to two luminescence transition of Er3+ ions: and . A mechanism of the luminescence intensity decrease has been proposed, in which deexcitation of the level to the level is caused by a neighbouring Er3+ ion being excited to the level. 相似文献
15.
John R. Lombardi J.Brooke Koffend Richard A. Gottscho Robert W. Field 《Journal of Molecular Spectroscopy》1977,65(3):446-454
Luminescence is observed from gas phase thiophosgene on excitation with the 5287 Å line of an Ar+ laser. Analysis of the emission spectrum shows that the emitting level is the one initially populated by laser excitation of the band. Using a tunable dye laser, an excitation spectrum near the origin of this triplet system is obtained and analyzed. It appears that the observed luminescence is resonance phosphorescence resulting from direct laser excitation into a vibronic level of predominant triplet character. 相似文献
16.
17.
J. Verwaest 《Nuclear Physics B》1977,123(1):100-108
We calculate in the 2-dimensional sine-Gordon theory the soliton mass Msol to order λ and compare it to the meson mass. We find This supports the belief that the field-theoretic WKB approximation of Dashen, Hasslacher and Neveu gives the correct answer for the sine-Gordon problem. 相似文献
18.
Revised and more complete vibrational assignments are made for the 3540-Å band system of malonaldehyde. The tunneling splitting is found to be 19 ± 11 cm?1 for the state and this represents a 7-cm?1 decrease relative to the ground electronic state. The tunneling splitting and the Franck-Condon envelope of intensities in the 185-cm?1 upper-state progression suggest that the state is significantly less tightly hydrogen-bonded than the ground 1A1 state. 相似文献
19.
V.V. Barmin V.G. Barylov I.V. Chuvilo G.V. Davidenko V.S. Demidov A.G. Dolgolenko A.G. Meshkovsky L.B. Okun V.A. Shebanov M. Baldo-Ceolin E. Calimani S. Ciampolillo F. Mattioli G. Miari A. Sconza 《Nuclear Physics B》1984,247(2):293-312
We discuss the accuracy of CPT invariance tests in the neutral kaon decays. The possible CPT non-invariance is parametrized by amplitudes of two types: (i) CP violating, but T conserving, and (ii) T violating, but CP conserving. It is shown that the experimental data are consistent with CPT symmetry essentially within two standard deviations.The source of this not quite satisfactory agreement is the experimental value of the phase φ00 of the ratio , which differs by two standard deviations from the phase φ+? of the ratio decay amplitude. We argue that to get better agreement with CPT invariance, the value of the phase φ00 has to be equal to the value of the phase φ+? within the errors of the latter. New, more accurate measurements of the phase φ00 would be very interesting to rest CPT invariance, especially taking into account that neutral kaons allow the test with much better accuracy than any other particle. 相似文献
20.
F.J. Hasert W. Krenz J. Von Krogh D. Lanske J. Morfin K. Schultze H. Weerts G.H.B. Coremans H. Mulkens J. Sacton W. Van Doninck D.C. Cundy D. Haidt P. Musset A. Norton J.B.M. Pattison F. Romano A. Rousset A.J. Segar 《Physics letters. [Part B]》1975,59(5):485-489
A study is presented of single πo production in neutrino and antineutrino interactions in Gargamelle filled with freon CF3Br. Limits on the neutral to charged current cross-section ratios and are found to be at 68% confidence level. 相似文献